Parents have their own choices but I am sure that parents do not want their kids to follow what wrong they do or did in their life.
Like if a father takes drug he would beat his son to death if he finds out his son is doing the same. Likewise - if the parents are addicted drinker they would not want their kids to do that, Having gambling trait in DNA is not correct - its a choice.
what you describe for parents I agree but not for DNA, there are many journals or studies that explain certain types of addiction, especially drugs, for example, as you mentioned, parents who use drugs will have the potential to cause addiction to their children even in a healthy environment. there are many journals that describe the inheritance of traits in DNA, you can look for it.
In the case of gambling, I think it is interesting that the inherited nature of gambling activities carried out by its predecessors is different from the inheritance of drugs, drugs are substances that are inserted into the human body so that it causes an addictive effect and this affects the DNA chain. For inheritance gambling, inheritance gambling is still very relevant for debate because I believe that everyone is equipped with knowledge and can choose and be responsible for each choice.